Primary Citation of Related Structures:   1W85, 1W88
PubMed Abstract: 
Thiamine diphosphate (ThDP) is used as a cofactor in many key metabolic enzymes. We present evidence that the ThDPs in the two active sites of the E1 (EC 1.2.4.1) component of the pyruvate dehydrogenase complex communicate over a distance of 20 angstroms by reversibly shuttling a proton through an acidic tunnel in the protein ...
Thiamine diphosphate (ThDP) is used as a cofactor in many key metabolic enzymes. We present evidence that the ThDPs in the two active sites of the E1 (EC 1.2.4.1) component of the pyruvate dehydrogenase complex communicate over a distance of 20 angstroms by reversibly shuttling a proton through an acidic tunnel in the protein. This "proton wire" permits the co-factors to serve reciprocally as general acid/base in catalysis and to switch the conformation of crucial active-site peptide loops. This synchronizes the progression of chemical events and can account for the oligomeric organization, conformational asymmetry, and "ping-pong" kinetic properties of E1 and other thiamine-dependent enzymes.
Related Citations: 
Molecular Assembly of a Multi-Enzymes Complex: The Crystal Structure of Pyruvate Dehydrogenase E1 Bound to the Peripheral Subunit Binding Domain of E2 Frank, R.A.W., Pratap, J.V., Pei, X.Y., Perham, R.N., Luisi, B.F. () To be published --: --
Organizational Affiliation: 
Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK.